From a2ea924e12dcaa12bfa2d0afae7fe185538a91df Mon Sep 17 00:00:00 2001
From: Rocco Meli <rocco.meli@cscs.ch>
Date: Fri, 31 Jan 2025 15:55:53 +0100
Subject: [PATCH] Cleanup LibXC handling in CMake

---
 CMakeLists.txt                           |  9 ++--
 cmake/modules/FindLibXC.cmake            | 60 ------------------------
 src/CMakeLists.txt                       |  2 +-
 tools/docker/scripts/build_cp2k_cmake.sh |  2 +
 tools/spack/cp2k-dependencies.yaml       |  2 +-
 5 files changed, 8 insertions(+), 67 deletions(-)
 delete mode 100644 cmake/modules/FindLibXC.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index ca44526349..3be38316eb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -588,7 +588,7 @@ if(CP2K_USE_ELPA)
 endif()
 
 if(CP2K_USE_LIBXC)
-  find_package(LibXC 7 REQUIRED)
+  find_package(Libxc 7 REQUIRED CONFIG)
 endif()
 
 # uncomment this when libgrpp cmake support is complete
@@ -822,10 +822,9 @@ if(CP2K_USE_CUSOLVER_MP)
 endif()
 
 if(CP2K_USE_LIBXC)
-  message(
-    "  - LIBXC (note to package managers : libxc can be build with cmake as well)"
-    "   - include directories : ${CP2K_LIBXC_INCLUDE_DIRS}\n"
-    "   - libraries : ${CP2K_LIBXC_LINK_LIBRARIES}\n\n")
+  message("  - LibXC\n" "    - Libxc_VERSION:  ${Libxc_VERSION}\n"
+          "    - Libxc_INCLUDE_DIRS : ${Libxc_INCLUDE_DIRS}\n"
+          "    - Libxc_LIBRARIES : ${Libxc_LIBRARIES}\n\n")
 endif()
 
 if(CP2K_USE_LIBTORCH)
diff --git a/cmake/modules/FindLibXC.cmake b/cmake/modules/FindLibXC.cmake
deleted file mode 100644
index cebb9f61f6..0000000000
--- a/cmake/modules/FindLibXC.cmake
+++ /dev/null
@@ -1,60 +0,0 @@
-#!-------------------------------------------------------------------------------------------------!
-#!   CP2K: A general program to perform molecular dynamics simulations                             !
-#!   Copyright 2000-2025 CP2K developers group <https://cp2k.org>                                  !
-#!                                                                                                 !
-#!   SPDX-License-Identifier: GPL-2.0-or-later                                                     !
-#!-------------------------------------------------------------------------------------------------!
-
-include(FindPackageHandleStandardArgs)
-find_package(PkgConfig REQUIRED)
-include(cp2k_utils)
-
-cp2k_set_default_paths(LIBXC "LibXC")
-
-if(PKG_CONFIG_FOUND)
-  # For LibXC >= 7, the Fortran interface is only libxcf03
-  pkg_check_modules(CP2K_LIBXC IMPORTED_TARGET GLOBAL libxcf03 libxc>=7)
-endif()
-
-if(NOT CP2K_LIBXC_FOUND)
-  # Revert pkg_check_modules side effects
-  cp2k_set_default_paths(LIBXC "LibXC")
-  foreach(_var xc xcf03)
-    string(TOUPPER LIB${_var} _var_up)
-    cp2k_find_libraries(${_var_up} ${_var})
-  endforeach()
-endif()
-
-if(CP2K_LIBXC_FOUND)
-  # Require both libxc + libxcf03 for LibXC 7
-  set(CP2K_LIBXC_LINK_LIBRARIES
-      "${CP2K_LIBXCF03_LIBRARIES};${CP2K_LIBXC_LIBRARIES}")
-endif()
-
-if(NOT CP2K_LIBXC_INCLUDE_DIRS)
-  cp2k_include_dirs(LIBXC "xc.h;libxc/xc.h")
-endif()
-
-if(CP2K_LIBXC_INCLUDE_DIRS)
-  find_package_handle_standard_args(
-    LibXC DEFAULT_MSG CP2K_LIBXC_FOUND CP2K_LIBXC_LINK_LIBRARIES
-    CP2K_LIBXC_INCLUDE_DIRS)
-else()
-  find_package_handle_standard_args(LibXC DEFAULT_MSG CP2K_LIBXC_FOUND
-                                    CP2K_LIBXC_LINK_LIBRARIES)
-endif()
-if(CP2K_LIBXC_FOUND)
-  if(NOT TARGET cp2k::Libxc::xc)
-    add_library(cp2k::Libxc::xc INTERFACE IMPORTED)
-  endif()
-
-  if(CP2K_LIBXC_INCLUDE_DIRS)
-    set_target_properties(
-      cp2k::Libxc::xc PROPERTIES INTERFACE_INCLUDE_DIRECTORIES
-                                 "${CP2K_LIBXC_INCLUDE_DIRS}")
-  endif()
-  target_link_libraries(cp2k::Libxc::xc INTERFACE ${CP2K_LIBXC_LINK_LIBRARIES})
-endif()
-
-mark_as_advanced(CP2K_LIBXC_FOUND CP2K_LIBXC_LINK_LIBRARIES
-                 CP2K_LIBXC_INCLUDE_DIRS)
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 12ab950185..26d41e4f10 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1609,7 +1609,7 @@ target_link_libraries(
     $<$<BOOL:${CP2K_USE_VORI}>:cp2k::VORI::vori>
     $<$<BOOL:${CP2K_USE_SPGLIB}>:Spglib::symspg>
     $<$<BOOL:${CP2K_USE_LIBSMEAGOL}>:cp2k::libsmeagol::smeagol>
-    $<$<BOOL:${CP2K_USE_LIBXC}>:cp2k::Libxc::xc>
+    $<$<BOOL:${CP2K_USE_LIBXC}>:Libxc::xcf03>
     $<$<BOOL:${CP2K_USE_ELPA}>:cp2k::ELPA::elpa>
     $<$<BOOL:${CP2K_USE_PLUMED}>:cp2k::plumed::plumed>
     $<$<BOOL:${CP2K_USE_FFTW3_}>:cp2k::FFTW3::fftw3>
diff --git a/tools/docker/scripts/build_cp2k_cmake.sh b/tools/docker/scripts/build_cp2k_cmake.sh
index 9d5095de51..ba69c38d40 100755
--- a/tools/docker/scripts/build_cp2k_cmake.sh
+++ b/tools/docker/scripts/build_cp2k_cmake.sh
@@ -182,6 +182,7 @@ elif [[ "${PROFILE}" == "toolchain" ]] && [[ "${VERSION}" == "pdbg" ]]; then
 
 elif [[ "${PROFILE}" == "ubuntu" ]] && [[ "${VERSION}" == "ssmp" ]]; then
   # TODO fix spglib https://github.com/cp2k/cp2k/issues/3414
+  # NOTE: libxc 5.2.3 is provided, CP2K requires libxc 7
   cmake \
     -GNinja \
     -DCMAKE_INSTALL_PREFIX=/opt/cp2k \
@@ -190,6 +191,7 @@ elif [[ "${PROFILE}" == "ubuntu" ]] && [[ "${VERSION}" == "ssmp" ]]; then
     -DCP2K_USE_LIBINT2=ON \
     -DCP2K_USE_LIBXC=ON \
     -DCP2K_USE_FFTW3=ON \
+    -DCP2K_USE_LIBXC=OFF \
     -DCP2K_USE_LIBXSMM=ON \
     -DCP2K_USE_SPGLIB=OFF \
     -DCP2K_USE_MPI=OFF \
diff --git a/tools/spack/cp2k-dependencies.yaml b/tools/spack/cp2k-dependencies.yaml
index 755976a95f..8d6ca63151 100644
--- a/tools/spack/cp2k-dependencies.yaml
+++ b/tools/spack/cp2k-dependencies.yaml
@@ -7,7 +7,7 @@ spack:
     - "netlib-scalapack@2.2.0"
     - "libxsmm@1.17"
     - "fftw@3.3.10 +openmp"
-    - "libxc@6.2.2"
+    - "libxc@7.0.0 +kxc build_system=cmake"
     - "spglib@2.3.0"
     - "dla-future@0.7.3 +scalapack"
     - "dla-future-fortran@0.2.0"